Psychologists' intervention in school disasters, as well as in community disasters affecting a school population, entails a major departure from their traditional role. This preliminary model is reconceptualized from the preventive model underlying community mental health intervention and modified to meet the specific needs of the school organization in disaster. Prevention in mental health is usually regarded as interfering with or inhibiting the development of crisis. The tripartite conceptual model includes primary, secondary, and tertiary levels of prevention. Primary prevention is carried out when a situation exists and it is directed at the general population not yet experiencing maladjustment in order to counteract potentially harmful effects; secondary prevention aims at identifying and resolving the crisis at the earliest stage of maladjustment; and tertiary prevention is the intervention made after the crisis has eased in order to minimize residual effects. For a school psychological service (SPS) to respond properly in an emergency, a reconceptualization of the tripartite prevention model has to be undertaken. This model focuses on an emergency response by introducing anticipatory intervention at the pre-impact level, and introducing as a separate step the reorganization of the SPS as an immediate response to an emergency. Also, the primary and early secondary measures are initiated concurrently and certain components of tertiary preventive measures are highlighted. 47 references, 1 table, and 1 figure. (Author abstract modified)